CometWatch 2 December

This four image mosaic comprises images taken with Rosetta’s NAVCAM on 2 December from a distance of 30.1 km from the centre of Comet 67P/Churyumov-Gerasimenko. The image resolution of the mosaic is about 3.1 m/pixel, and it has been cropped to measure 4.5 x 3.6 km.

Four image NAVCAM mosaic comprising images taken on 2 December 2014.  Credits: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0

Four image NAVCAM mosaic comprising images taken on 2 December 2014. Credits: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0

Each original 1024 x 1024 pixel frame (provided below) has a scale of 2.6 m/pixel and measures nearly 2.6 km across.

As usual, before interpreting the mosaic, do check the original frames, because the rotation and translation of the comet during the image sequencing makes it difficult to create an accurate mosaic. In this particular instance, some distortions were needed in order to get the images to align, which also resulted in the slightly different image scale.


In this orientation, the smaller of the two comet lobes is towards the left, the larger lobe towards the right.

It provides an almost “face-on” view onto the large depression on the smaller lobe, its boulder-strewn surface albeit enshrouded in shadow. On the other hand, the internal walls are seen in quite some detail. It is thought that Philae’s final touchdown site might be located close to the rim of this depression but further high-resolution imaging is still being obtained and analysed to confirm this. This depression, measuring almost 1 km across, was once considered as candidate landing site B.

This orientation also provides a good view onto the plateau that was previously considered as candidate landing site A – close to the ‘join’ between the two right-hand side images frames. The dark circular region is a large pit. The cliff walls that drop down onto this plateau seem to show slightly brighter sections, perhaps reflecting compositional differences, or fresher material that has yet to be degraded by exposure to the space environment.

The four individual images making up this mosaic are provided below.





  • Dave says:

    Does anyone who believes that sublimation is the prime errosion mechanism have a theory on how sublimation delivers a terrain like this.
    No rounded features, many sharp features and straight lines. Lots of craters or holes that from afar, you could just about think these features were from collisions. However from close up, It just does not ring true.

    We all would expect some ices on the comet almost what ever was its birthplace. So if ices are there then there has to be sublimation, assuming the conditions are right for what ever ice we have.
    However look at the surfaces, this has not been produced by sublimation.
    We have a tested method for electrical errosion, but as the lab data says and Proffessor Harvey points out, at the energies tested there is not enough water produced to account for the coma and tail.
    I can imagine that both these methods are currently operaring at some places on the comet where conditions are right even as we are looking on,
    So even if both these are operating, what is producing the scarred landscape, paired craters, small craters paired diametrically opposit on the rims of some large craters? Also large scollopped valleys and tracks running for over a kilometer across the surface. Lots of straight sided polygon shapes, large over hangs and caves are also apparent, often with thin walls left standing, why if sublimation is happening does this outlandish terrain exist? These thin walls should be fading away before our eyes as the phase change from solid to gas slowly does its invisable work.
    My guess would be that there are some collision effects, but there is no way these are responsible for the main features. We are missing something very big.
    Nor do I believe there is much plate techtonics or geological pressure going on in the main lobes, possibly in the neck, but the neck is smooth, so that still would not explain the rugged terrain.
    What we have to explain is not how soft snow or ices sublimate, the elephant in the room is how does this hard strong surface, whether its Ice, dirty snow, ice reinforced by dust, or rock get its shape???
    Sublimation just does not do it for me.

    • Jacob nielsen says:

      @Dave, to me a hard crusted icy body, that blows out dust, that settles again to some extend, while the body is shrinking in the process, would turn out just like this.

    • Gerald says:

      Subsurface sublimation may form caverns which could collapse, leaving crater-like structures. It may also cause caverns filled with pressurized gas, which at some point may lift the covering layers and erupt, like kind of a volcano, leaving a crater-like caldera or maar.

      • Robin Sherman says:

        The thermal conductivity of the surface layers of the comet are a major goal of the Rosetta team. Your suggestion makes a lot of sense Gerald. There does seem to be a distinct underlying "cellular" pattern and structure to the whole comet. The containing walls of such caverns would be defined by regions of less volatile materials, the "cell walls" as such, which by there nature would survive longer when exposed at the surface. This would require a non-homogeaneous mixture of materials inside the comet. This could be explained by the porous nature of the material and the gravitational and centripetal forces acting on it.

    • originalJohn says:

      Well Dave your judgement is sound. There is no evidence of sublimation of ice on this comet nucleus neither has there been on any other. Yet there is a group to whom it seems important to keep that particular myth alive. They work hard using primitive maths to show that electrical effects are not operating. The mathematics would only have relevance if they understood and were able to quantify the environment they are dealing with. Clearly they do not and are not so they are left with guess work based on misguided preconceptions. One has to wonder why they are so keen to preserve such an ignorant interpretation of comets which has no scientific basis whatsoever, and in the face of the now considerable evidence of the electrical nature of this and other comets and the electric currents that flow throughout the heliosphere. It is clear that the Sun, the planets and interplanetary bodies are not neutral and isolated.

      The significant measurements relating to plasma and electrical properties on this mission have yet to be released. When they eventually are what is already obvious will be confirmed and the ice sublimation myth will be dead and buried for good. Then perhaps some interesting and worthwhile science can begin.

      • Gerald says:

        The comments of mission scientists I heared thus far tell the contrary:
        No evidence for the electrical comet hypotheses.

    • Robin Sherman says:

      You've hit the nail on the head there Dave. Glad its not my job to explain that "big Elephant". The small scale erosion by sublimation can explain some of it, for instance how "crater" rims are left standing, but the great walls of cryorock, vast chasms and mountains, thats a whole different ball game. The very linear and polygonal features are likely to be a function of the low gravity and a semi crystalline nature to the cometary material would be my guess, but exactly how that works I have no idea and I shouldn't think too many others have either. Some sort of cryovolcanism has played a large role as well, the energy source for which I can only guess comes from impacts or the Sun has a lot more drastic effect than anybody thinks.

      • Ross says:

        Cryovolcanism is hypothetical and indirectly observed. On Enceladus, for instance, the 'volcanoes' are inferred based on the presence of water vapor and dust production. A popular plume, Prometheus, is known to be moving across the surface. It is a fact that electric currents connect the ionospheres of Saturn to its moons. The mechanism is exactly the same as the 'jet' formation on comets, a discharge between the surface and the ionized environment.

    • idjles says:

      i see the answer starting me in the face all through winter in our "earthly comets": uneven reflection off dirt+uneven surface+loss of matter internally causes the sharp features.

      Snow heaps have daily cycles of warming in the sun and subliming (& melting down to the street - effect is the same of hollowing), freezing at night, and the surface is rough and spiky and VERY HARD. If any piece falls or lands on it, it merges into the other during the day and freezes solid to it overnight.

    • Kasuha says:

      I have no problem with sublemation as main driver of comet's erosion. Of course I did not do any simulations but I see it as very plausible that the comet is made from a mix of fine primordial dust (both volatile and non-volatile) and some secondary material, i.e. boulders that were parts of bigger bodies closer to the Sun which were later destroyed in collisions and driven to the outskirts of the system by gravitation of gas giants.
      The comet material is not perfectly homogenous or isotropic. This means at certain places there's more of volatile material, and at other places there is less of it. When the comet gets closer to the Sun, places with higher concentration of volatile material are outgasing more and drive more non-volatile dust along. As a result, bottoms of "craters" may be just covered by thinner layer of dust, and rims may be covered by thicker layer, leading to generally slower heat transport, and slower outgassing on these protrusions compared to depressions. The "neck" may be just an extreme case of the same mechanism.

      Of course things are likely more complex than just that.

      I can't gíve any merit to claims about the comet being electrically charged. Solar wind is plasma - collection of both positively and negatively charged ions traveling from the sun. If the comet was electrically charged somewhere in the history, it would repel particles of the same polarity and attract particles of the opposite polarity, effectively neutralizing its initial charge within historically very short time. There's no way it could keep its electric charge all the time up to now.

      • originalJohn says:

        Kasuha, any mechanism involving sublimation to explain the surface features of this comet nucleus would first need to positively identify the sublimating material, on or beneath the surface, and this has yet to be done.

        With regard to electrical properties as you say the solar wind is a plasma. Calling it a wind is, however, a confusing misnomer as it is not a wind ( ie mechanically driven particles) at all. It is a flow of charged particles otherwise known as an electric current. In general protons flow from the Sun towards the edge of the heliosphere which acts as a virtual cathode. This is caused by the very high influx of electrons from the interstellar medium. Electrons flow from this cathodic region towards the Sun. This current flow is not simple and uniform and many local complexities can occur, including drift of electrons in the same direction as protons. Overall though as in any plasma current the positive and negative ions flow in opposite directions.

        The charge carried by the comet nucleus varies with its orbital cycle. This short period comet becomes more negatively charged beyond the orbit of Jupiter and progressively discharges, becoming more positively charged as it approaches the Sun, then returns to a more negative state of charge as it approaches aphelion again.

        There are instruments on both the orbiter and the lander capable of measuring this charge and indeed its variation as the cycle proceeds. One would imagine this would be a priority.

        • Gerald says:

          Basics about solar wind:
          "SOLAR WIND
          A stream of particles, primarily electrons and protons, flowing outward from the Sun at speeds as high as 900 km/s. The solar wind is essentially the hot solar corona expanding into interplanetary and interstellar space."

          cited from

      • Ross says:

        That is wrong. Hyperion, a moon of Saturn, is negatively charged with respect to Cassini which discharged from over 2000km away earlier this year. Your reasoning is flawed because you're not taking into account the incredible difference in mass, and thus velocity, between protons and electrons given the same kinetic energy. Do a search for double-layers and why they exist in plasmas.

    • Kamal Lodaya says:

      Dave: Sorry, I just posted on the 30 November image blog that the H2O production has jumped six-fold (already before November), as reported by Rosetta scientists at the DPS meeting in Tucson. Am happy that you accept that sublimation may be taking place in addition to othet things, because don't understand how otherwise so much H2O would be delivered to the coma. As to the strange surface features, no one has a definitive understanding of them yet. I imagine the analysis of the experiments conducted by Philae will give some answers.

    • Bruce says:

      Hi Dave,
      Bill Wilson, a regular contributor to this blog, has provided a superb geological analysis of the possible processes at work on his SmugMug site. See especially this series - lower on the page here:
      He shows how gaseous processes can produce several different types of terrain including: effusive deposits, scree deposits, plumed deposits, pitted terrain and deflated terrain. And that's just near the Philae landing site.

      The other thing to rmember is that sublimation can produce gases at substantial pressures, and there is little gravity to hold material to the surface. The comet is largely held together by frozen ices. Pockets of these will melt due to local heating effects. Eventually the pressure will become high enough or the cohesive stregth of the local overburden will be lost and the gases will erupt with considerable force.

      • Ross says:

        The 'effusive deposits' image shows an excellent example of electrical erosion. The distinct scalloping of the raised edge is characteristic of electric discharge machining and is caused by the rotating arc gouging material from the ridges.
        The sublimation model predicted that the surface would be covered in ice at the current distance. This was a failed prediction which doesn't falsify the sublimation, as the ices could be entirely hidden beneath the surface. I like to emphasize the necessity of indirect observations to support the foundation of this outdated snowball model.

        You say that the comet is "largely held together by frozen ices", however, the cliffs of the neck region present the most recent erosion and exposed interior of the comet. I see no pockets of any kind, rather, it looks just like a rock. Collimated jets are all over the nucleus yet I have seen zero nozzle-shaped vents leading to sub-surface cavities, which are required to produce the phenomena we observe.

        • Bruce says:

          Ross I can't comment either way. I have no particular expertise in electrical erosion or sublimation erosion.

      • Bruce says:

        Sorry that should be Bill Harris, not Bill Wilson. My apologies Bill!

    • AndreH says:

      Just 2 days ago we got some 5 centimeter of snow. MY daughter and neigbour kids have been building snow mans. Two days later the sun was out melting the poor gux dow. On the surface of the molten left over I noticed the exact same features: polygonal craters, sharp rims, uneven erosion in the neck region (of the snow man) etc.
      The funny thing is I only realised that patterns because of this (to me) totally illogic discussion here abot EU theory which cannot explain how Rosetta travelled to the comet in first place.
      If 1+1 = 2 and 2 + 2 = 4 then 1 + 1+1 +1 = 4, not 5 or 3

  • Gerald says:

    In case, this is not the 100th comment about the link of the first (stitched) image: It's referencing a 30 November image.

  • Gerald says:

    CIVA Panorma 1, Cameras 5, and 6, processed:
    Camera 5 image is intentionally upside-down, to account for the lighting conditions, which simplifies perception by turning the image.

    • Robin Sherman says:

      Nicely done Gerald, considerably better than my efforts. It looks like you have adjusted for the perspective as well. Many thanks, I was hoping someone could do a better job than me.

      No need to look for evidence of sublimation any more. Image 6 in particular, the cryorock is covered in little pits and holes. As Dave says above, the large scale features on the surface require a whole new explanation. The extended plates and ridges, cliffs and ravines in particular. Things may look a whole lot different on the surface when 67P gets nearer the Sun.

      • Gerald says:

        The geometry is that of the raw images, as provided by ESA, see also my answer to Dave, below.

        • Robin Sherman says:

          Thanks Gerald. I cut mine out of the complete panorama. I new the individual images were somewhere, they appeared on one of the blog pages here, but I could not find them. What we know now is that little Philae is stuck in a tight spot and seems to have been unbelievably lucky to land reasonably upright. Unfortunately the spot where I think Philae sits, is hidden in shadow in the image above. What I did notice is the alcove type nook she is in is a fairly common formation. There are two remarkably similar "alcoves" at about 11 O'Clock from the left horn of the big crater. One close to the rim edge and the second larger one just above it. I hope they are extinct, not dormant, vents.

  • idjles says:

    The more I look at the comet, the more it looks like the pile of dirty snow that the snow plough dumps in front of my property in the early morning after a snowy night.
    After a number of sunny days and bitterly cold nights, it ends up being dirty, VERY HARD and spiky and rough in the surface and softer underneath.
    I just imagine the comet coming towards the sun - and warming up the incredibly hard rough dirty surface - it sublimates/degasses/whatever until "sunset" when it heads out beyond Mars to the cold night where it goes rock hard again on the rough surface.

  • Sovereign Slave says:

    Well, I never got hooked on phonics, but I currently seem to be hooked on sublimation. It is a fascinating subject, and while I know I’ve bashed the idea of it for P67, I also know it’s very reasonable to assume that if there is ice or other frozen volatiles there, they’d no doubt be sublimating as temperatures rise. So in that context, as I looked at this picture, something occurred to me. This may seem painfully obvious to my fellow peanut-gallery-going back seat drivers, but here’s the question.

    Where did all the dust covering the comet come from? Again, seems like only three possible options. Either all the dust we see is native to the comet and has always been a part of its makeup, or the dust has been created through some natural process, or a combination of the two.

    According to the sublimation theory, the only explanation that seems possible is that the dust has always been a part of the comet, which I guess is the case with dirty snowballs. According to the theory, they have to be formed of ice and dust and not rock because there is no process for breaking down the rock into dust. Sublimation certainly wouldn’t be able to do it, and I can think of no other process (besides electrical machining) that would create so much dust. Sublimation could release dust that was mixed in with the frozen volatiles, but it certainly wouldn’t break down rock into fine dust power, nor would anything else I can think of that P67 would encounter in space. So according to the theory, all the dust we see has always been part of the comet, and the dust must be pretty much evenly mixed throughout the interior as well.

    When I look at the picture above and the other pictures, my lying eyes see rock and dust, and I assume that the dust wasn’t native to the comet, but that it’s probably been created from electrical tooling that has acted on the rock. Fascinating to me how our minds tell our eyes what they’re seeing. Case in point, I don’t think anyone is saying the stuff on the comet that looks like dust isn’t REALLY dust, though many are saying that the stuff that looks like rock isn’t REALLY rock. Why is that? Again it comes down to belief. According to the dirty snowball theory, all the non-dust has got to pretty much be some form of frozen volatiles and dust. There’s really nothing else it could be, so for them it simply doesn’t look like rock because it can’t be rock.

    But bottom line, snowball means the comet is made of dust, whereas rock most likely means dust is being generated by the same process that then carries it into the coma (otherwise, how would it get into the coma?).

    • Sovereign Slave says:

      Just to be clear, when I said, "Fascinating to me how our minds tell our eyes what they’re seeing," I was also applying it to the sentence before it.

    • Allan says:

      >According to the theory, they have to be formed of ice and dust and not rock because there is no process for breaking down the rock into dust.

      In the early solar system there would be larger objects that were then smashed apart into boulders, dust etc. The comet forms under low gravity and so attracts that dust, boulders, water ice, other volatiles etc. When the ice sublimates and is trapped and explodes out under pressure it would also fling boulders around, demolish structures etc. All of this creates more dust. There is no need to invoke the unproven EU model to come up with what we are observing.

      • Sovereign Slave says:

        Hi Allan, regurgitating speculation about what happened in the “early solar system” does not confirm the speculation, and is also completely unproven. And it’s not science to invent creation myths that are absolutely impossible to prove, and then present science through the guise of that myth. Yet a huge amount of standard model theory is enamored with trying to explain the origins of the universe, what “was,” and then use that to explain what “is.” It’s a totally upside down red herring. Here’s a news flash…in reality no one has the vaguest notion of what the origins of the universe are (or if the universe even HAD an “origin”) and certainly no one can scientifically prove or even intelligently guess as to what the origins of the universe are. And standard model theory is running out of glue and duct tape to hold that dialogue together. It’s continually discrediting itself with each passing new discovery. Even with P67 the dialogue continues to change as it tries to explain the many inevitable surprises. It’s the standard pattern. First initial surprise at no surface water, comet color, comet surface temperature, comet shape, surface hardness when Philae bounced (as stated in the debrief), the high comet activity and die down in April, and now the inevitable ad hoc explanations trying to explain and normalize these surprises – ice is all subsurface, maybe uneven volatiles caused early flare up and comet shape, it’s not rock but is rock like (weird to me how standard model acknowledges that asteroids are made of rocks, and how much asteroids look like comets, but comets are definitely not rocks). Too much of standard model theory is too internally self-contradictory, unprovable, outrageously fantastical, and unsubstantiated. And while all this stuff makes for great science fiction movies, more and more, gravity alone is proving itself to be an inadequate force to explain the things we observe and measure in space. EU theory doesn’t concern itself with origin of the universe questions, and while much of the theory is also currently unsubstantiated, it’s a simple fact that it’s gaining more and more ground as a working model to explain what we observe in space, and much of this is because virtually every new discovery seems to support it. Hopefully much more science will be fully and objectively revealed about P67, and I guess I’m willing to wait till August 13 and maybe much longer to see it. But I bet that they find Philae long before they find any ice.

        • Allan says:

          >in reality no one has the vaguest notion of what the origins of the universe are (or if the universe even HAD an “origin”) and certainly no one can scientifically prove or even intelligently guess as to what the origins of the universe are

          With a wave of your hand you dismiss the massive amount of work done on how the universe came about.

          >EU theory doesn’t concern itself with origin of the universe questions, and while much of the theory is also currently unsubstantiated, it’s a simple fact that it’s gaining more and more ground as a working model to explain what we observe in space, and much of this is because virtually every new discovery seems to support it.

          I think you are dreaming to think that there are scientists supporting the EU hypothesis. Though i suspect you assume there is a conspiracy in place to hold back the TRUTH (and why would that be?)

          • Sovereign Slave says:

            If you think that anyone can accurately determine much of anything that was happening in history (cosmic or otherwise) even 10,000 years ago, much less a million, or a billion, or tens of billions (if that’s even the case), then I’ve got some beach front property in Kansas you may be interested in. Again, this stuff makes for great marketing material to keep the public coffers flowing, but it is totally invalid to dress up as science some purely speculative theory about the distant past and present it as fact when explaining present day phenomena. But over and over this mythology has been presented as the truth, to children on up. And that’s a trap, because people tend to not question something once they are told it is true, especially when those truths have been indoctrinated as the social norm. Is EU theory true? Perhaps, perhaps not, but I think at the very least it’s the best theory with which to question and appraise the most basic foundations of the largely unchallenged standard model theory.

            As far as physicists/scientists involved with Electric Universe theory, here are two very partial lists:



    • Kamal Lodaya says:

      Sovereign slave: You seem to see only two theories, dirty snowball and electric universe, and keep telling us about paradigm shifts. There are other possibilities, and I imagine many of the people on this blog might not be tenaciously holding to any one of the two you mentioned, because they aren't interested in seeing paradigm shifts everywhere.

      "if there is ice or other frozen volatiles there"... Okay, let us suppose there isn't any ice anywhere in or on the comet. Why has the H2O in the coma gone up six-fold? Where is it coming from?

      Everybody has seen over the last few months that more and more stuff seems to be leaving from the comet into the coma. And according to the Rosetta experiments (which constitute a small sample) the bulk direction is from the comet to the coma and not the other way around. Why is this emission activity increasing?

      Understanding the present raises questions which we have a better chance of answering. Asking questions about the past requires construction of a narrative and then one gets trapped in one's own theory.

      • THOMAS says:

        @ Kamal Lodaya

        “You seem to see only two theories, dirty snowball and electric universe, and keep telling us about paradigm shifts. There are other possibilities, and I imagine many of the people on this blog might not be tenaciously holding to any one of the two you mentioned, because they aren't interested in seeing paradigm shifts everywhere”.

        Science has nothing to do with what people are “interested in seeing”. What is at stake here is quite simply the most basic of scientific truths imaginable: are the mechanics of the Universe we inhabit being driven by gravity alone (whatever “gravity” is…), as standard Big Bang theory would have it, or by the almost infinitely more powerful (and scalable) force we call electricity (just that tiny +/- difference)?

        With all due respect to those who have their own pet theories and who are naturally entitled to express and explain them on this forum, it is this fundamental question about primary causes which accounts for the predominance of the “snowball/EU” dichotomy on this forum. One of these two models is necessarily right and the other is necessarily wrong. This is the issue which needs to be addressed first, hopefully by the aptly-named, “game-changing” (to quote mission scientist Matt Taylor) Rosetta mission. (I sincerely hope he meant that *the game is changing*, and not that *the rules of the game are being changed*, as has so often happened in the past with each successive patch to the BB model….). Only when this frontal opposition between two irreconcilable paradigms has produced an undisputed winner will we be able to address the more marginal theories which many people are interested in, some of which may subsequently indeed be found to be more or less compatible with the winning paradigm.

        But let us make no mistake; we first need to establish whether we live in a “gravity only” Universe or in an electrically-driven Universe. That is what is truly at stake in the Rosetta mission.

        And the stakes are sky-high, because of the catastrophic domino effect which any paradigm shift would trigger in the world of current academic science, as was the case in the early 17th century with Galileo’s famous observations of Jupiter’s moons. This also explains, finally, why the “dirty snowball” model is being, and always will be, so fiercely defended, in the face of gainsaying prima facie evidence, by the present astronomical Establishment.

        There is simply too much at stake for it to be otherwise.

        • Marco says:

          Re Thomas "it is this fundamental question about primary causes which accounts for the predominance of the “snowball/EU” dichotomy on this forum. One of these two models is necessarily right and the other is necessarily wrong."

          I must vigorously protest. I disagree MUCH more with this false dichotomy between EU and snowball, than I disagree with either theory, and believe me, I think EU is a slam dunk to be disproven, and similarly for solar/thermal/sublimation models. The primary "cause" may or may not have anything to do with why we cannot get our models around comets yet to predict behaviour and what our instruments might show next. I believe there is no "primary cause" as such. We will be able to explain the comets behaviour with, more or less, what we know about physics and science generally. It is parts of the narrative of the imagined history and energy sources of comets, as well as the source of its behaviour that needs complete rethink. We cannot just "invent physics" that explains the unexplainable, and we cannot just persist with a model with so many contradictions and so little predictive power. It's time for a multichotomy, not a dichotomy.

        • Marco says:

          Re Thomas "it is this fundamental question about primary causes which accounts for the predominance of the “snowball/EU” dichotomy on this forum. One of these two models is necessarily right and the other is necessarily wrong."
          I must vigorously protest. I disagree MUCH more with this false dichotomy between EU and snowball, than I disagree with either theory, and believe me, I think EU is a slam dunk to be disproven, and similarly for solar/thermal/sublimation models. The primary "cause" may or may not have anything to do with why we cannot get our models around comets yet to predict behaviour and what our instruments might show next. I believe there is no "primary cause" as such. We will be able to explain the comets behaviour with, more or less, what we know about physics and science generally. It is parts of the narrative of the imagined history and energy sources of comets, as well as the source of its behaviour that needs complete rethink. We cannot just "invent physics" that explains the unexplainable, and we cannot just persist with a model with so many contradictions and so little predictive power. It's time for a multichotomy, not a dichotomy.

    • Graham Hall says:

      Well the density of the comet overall is about 0.4gm per cubic cm.

      So the density is not rock and not water - its a fraction of both of those. The crust that we see is one thing; the interior may be different, having not been subjected to countless passes around the sun (the orbital period is only around 6.5 years!).

      Ice can break down rocks on earth due to its expansion when freezing and if the comet is a dirty snowball then dust would be left behind when the water sublimates. And the comet is as black as coal/charcoal. Its not made of earth type rocks, but again the colour (or lack of it) suggests carbon.

      Star evolution tells us that carbon will be produced in abundance as stars age - its very common. So is hydrogen and oxygen hence water. The dirty snowball fits the known facts and until we get something to the contrary I'm happy enough to go along with the consensus.

  • Dave says:

    Fabulous Gerald
    Where did you get those pictures are there more?
    Where is the location?

  • Bill says:


    Yelle-et_al, is an excellent reference.

    With my own work, this is an image of a possible location for the North Polar Dust Jet vents:

    with more comparative images in this Gallery:

    and Dust Jets at:


  • John says:

    Was not the scarred landscape created while it was in the asteroid belt bumping into its neighbours, before it finally broke free to roam the solar system ?

  • ricko says:

    The gravitational forces holding this thing together are minute, and it is rotating. At some locations, parts of it may be on the verge of drifting free. There must be a constant battle between gravity, centrifugal force, and whatever chemical and mechanical forces of cohesion are present.

    • Marco says:

      Don't forget tidal forces. By my reckoning, the sum of tidal and centrifugal forces should lift things off when aligned.

  • Bill says:

    This is something new-- some of the "moving snowflakes"-- streaks-- are appearing as dotted lines, like the particle is rotating as it's moving. Especially noticeable in the "B" image of the montage.


  • A.Cooper says:


    Well said. Everything you describe would be satisied by a historical close pass to Jupiter under the Roche limit. This would detach the head from the neck (you can see the shear line in this post's montage) and lift vast slabs from the surface as it did so. I have suggested on another Rosetta blog that a Roche pass explains the terrain we see: the detached head; the extruded neck; the ridge all round the body following the same line as the neck; vast areas of rugged terrain that lacks dust but is strewn with boulders; curiously rugged 'crater' rims that resemble shattered marble; detritus at the base of these rims.  

    There are several comments of mine at this link from the Landing Site Narrows blog post of 25/08/2014 which go into detail on the mechanism:

    Those comments include which rings of Jupiter it would most likely have passed through and a tentative suggestion as to how to look for a chemical signature of those rings on the comet. 

    As for the picture in this post, you can see the shear line where the head detached from the body in the bottom right quadrant. I have no means of annotating photos. Marco said in the above link to try and explain what I mean and it's a bit daunting without labelling but I'll do my best to describe it. This is based on comparing each and every photo from every possible angle, not just this one- I already knew where the line was and this just confirms it. I'll boldly state everything as fact, otherwise my description will be stuffed full of conditionals and qualifications. It's
    best to download the bottom right photo in full res. 

    1) start at the bottom about a third of the way from the left at the point where the left edge of a vertical shadow begins. 

    2) follow that left edge of the shadow up. This is almost right on the shear line itself. It's actually giving rise to the shadow. Everything to the right of the shear line slopes quite steeply away (into frame) but you can't tell that at all from this vertical viewpoint. 

    3) where this left edge of the shadow stops at a slight peak (coming out of frame at us) there is a faintly brighter three or four dots at an angle leading to another ridge that casts a much thinner shadow to its left. This starts with a small curve at the bottom end and leads to a larger curve above. You are now around a quarter of the way up the frame. There is one small, bright spot breaking the shadow on the reverse curve half way along between top and bottom curves. The larger curve at top makes a deeper, wider, curved shadow to its left with the ridge turning left above it to sit exactly horizontal to the frame. This horizontal section of ridge is very prominent from a sideways point of view and matches a deep kink in the head above.

    4) this horizontal-to-frame ridge then turns and continues somewhat steeper than 45 degrees, up the frame and slightly to the right, with little shadow to its left. Indeed, the ridge is bright here because you're seeing the drop to the left of it, down into the frame, where the head sheared off leaving brighter rock (not the brighter rock in site A mentioned in the post). 

    5) This ridge continues past a small peak to its right casting a stubby shadow towards bottom of frame. This small peak has two mini peaks atop it, the bottom one being quite bright. This is about a third of the way up the frame. As the ridge passes the upper left part of this shadow, the left edge of the shadow constitutes the shear line.

    6) the top left mini peak where the shadow ends is right on the shear line. The shear line continues at the same angle as it had before the shadow but is less pronounced because the slope to its left is less steep. But you can still see that slope (fractured rock) to left and dust to the right of the shear line. 

    7) this less pronounced line passes a horse shoe shaped shadow to its left. This shape is one
    of several nested curves (out of view) that are mirrored on the underside of the neck. 

    8) the shear line enters into shadow just beyond the horse shoe (vertical shadow in centre of frame). It continues in the same direction as it had been going ie straight up the length of the shadow. 

    9) the shear line then emerges from the shadow and angles left a bit becoming a flat slab with no discernible shear line. This is because a flat, splayed feature on the head that matches it, used to sit straight down on top of it. This (comparitively) flat slab is partially obscured at left by the furthest protrusion of the head in the foreground (in deep shadow). This protrusion, though part of the head, serves to guide us round to the next part of the shear line on the body: a flat area, mostly in shadow with a ridge above it that leads up to site A. That ridge used to be attached to the sharp point you see on the head, which in this frame protrudes over site A beyond it. There are two ridges leading up to site A. I'm referring to the lower one with the flat section at the bottom. 
    Another protrusion on the head (not quite visible) used to sit down on the other side of this flat, shadowed area ie at the far end of the 'slab' area on the body.

    10) the shear line then continues a little way along the edge of site A. In effect, it carries on all the way across it but there are small anomalies here that suggest lost or sunken material. However, you can see scalloped breakage marks covered in dust along the front edge. These roughly align with identical features on the head. That is, identical in appearance but not fitting together. These head features are not visible in this photo.

     No more definitive matches occur in the small section left at top of frame. This less coherent shear line is possibly due to the fact that the whole of landing site A is a very large missing slab that was sheared off as the head uplifted. You can see the small teeth-like sheer lines around the back rim, the 'shattered marble' appearance around the rim, the detritus left behind and a whiter, younger appearance as referred to in this post. This entire slab would have drifted away and been lost in the Jupiter Roche pass. On the whole, the perimeter of site A looks as though it's undergone a major upheaval.

    Another lost slab area is visible to the right of the shear line at the bottom of the frame. Again, this would have been levered up by the shearing of the head but didn't have the integrity to stay attached to it as it continued up so it drifted away due to differential g forces in the Roche pass. 

     The slab from site A appears to have stretched far beyond it, right to the cratered area at the far flank of the comet (out of this frame but in the top right frame). This would explain the bizarre, ragged, scree-strewn landscape bordered by soft, dusty craters.

     Landing site A's flatness could be explained by the fact that this slab sheared off at a stratum layer at this point. How a comet could lay down strata is beyond me but the head appears highly stratified and several other features in the shearing process have evidence of this including the largely flat underside of the head. The Roche pass would've worked on these weak points, shearing them and then extruding the central neck section, rather like pulling and cracking a chocolate apart and extruding the soft centre between the two halves. 

    There is also a missing slab area on the base of the comet (same ridges and scree features- see comet watch 1st December, left hand frames). This is where you'd expect material to come adrift in a Roche pass due to higher delta g at the extremities. 

    Marco suggests spin-up of the comet as an explanation of the extrusion. His comments are in the same link above. 

    • Marco says:

      Hi A Cooper, thank you for that. The scientific establishment (I mean that in the nicest possible way) appears to still be ignoring the "stretch" reasoning for C-P's shape. It still appears to be ablation vs. contact binary, with calculations such as density of the separate lobes possibly hinting whether they are related or distinct.
      I was wondering whether and when tidal forces from the Sun and or Jupiter combined with the centrifugal forces would overcome gravity at the extremities. I haven't done the calculations, but alignment of these forces should overcome gravity even at current distances to the sun.

      • A.Cooper says:


        Although the sun and Jupiter will have tidal influences on any body in the same manner as the sun and moon do for the Earth's oceans, it's a lot less than the forces involved in the Roche pass. So while 67P/C-G is out in relatively deep space, I'm relying on your spin-up theory. It's the only game in town as far as I can see, or at least until another very close approach to Jupiter occurs. That isn't envisioned in the JPL close approach tables that go to the year 2172.

         So the Roche pass theory can only explain the initial stretch and possible slab loss but can't have any ongoing influence, even at fairly close approaches to Jupiter of a million km or so. It may also explain the ~12-hour rotation because that is commensurate with the main phase of the Roche pass and the rocks have a tendency to dip, long axis down, at closest approach, being forced to spin on exit (in our simulations, that is). However, spin-up by sublimation seems very likely too:

        The 67P Wiki article now refers to the belief that the spin-up from 12.7 hours to 12.4 hours is due to sublimation-induced torque. That's what you said before, based on the difference in the 2009 light curve data (12.76 hrs) and the 2014 Osiris data (12.4hrs). That was a perfectly reasonable deduction to make but to strengthen your case, Lowry et al's August 2014 paper (ref 5 in Wiki article) now states it as being probable and uses the same data sources as you cited. As far as I can remember there was no mention of this 2014 paper when I last looked at the Wiki article. I had queried whether the Osiris data was simply more accurate than the 2009 data due to being so much closer to the comet but conceded that the error bars in the 2009 data were too narrow for it to be very far out at all. 

        I'm glad it's now pretty well official that sublimation is causing big rotation period changes. I'm now hoping the big crater on top is going to start getting active. I mentioned to you that it was head-on to the sun (within 15 deg) for two months. I think it was May and June or possibly from April 20th or so.  

        Incidentally, I'm now thinking that crater on the head may be a missing slab. Someone else first mentioned that a few weeks ago. It would be a likely candidate to be shed at such an extremity. Also, its depth is commensurate with the thickness of the strata we see on the head. One photo shows the strata lines very clearly, three parallel lines, and the 'top' one runs in line with the base of that large crater on the head even though the crater rims are still there. Photo here:

        So it's as if it's been gouged out leaving its flat shear layer below. That would be rather like landing site A. If a slab was indeed lifted from site A, it broke leaving a flat shear layer and depositing dozens of smaller slabs from the underside of the main slab. Those smaller slabs can be seen sitting at the back of the site A 'crater', beyond the flat part. 

        I should think there is big store of volatile material under that large head crater because, if the head was stretched from the body, Robin Sherman's cryovolcanism may have occurred in the neck leaving veins of purer ice. Just a thought. It's not getting much sun right now but perhaps soon it will stir and lead to a fast spin-up (or spin-down). 

      • Marco says:

        I was mentioning the tidal forces for a couple of reasons. Firstly, rocks and loose dust on the extremities should be lifted at moments of alignment around May. This will show whether some of the boulders are attached or loose.
        Secondly, tidal forces may induce a tumble or wobble to the axis of rotation. This may expose unexpected parts of the nucleus to the sun or different forces.
        Thirdly, depending on the mass distribution, and differential tensile strength, aligned tidal forces could lead to a pulsating tensile force transferred to the more elastic part of the neck.
        I actually agree with you in regards to "stratification" and the "lost slab" hypothesis to explain the unusual flat bottomed craters and associated "rubble".
        There seems to be a process whereby roughly parallel plains of material are layered on many parts of the comet, and, as you say, events which can dislodge relatively large slabs of those layers.
        Still no bona fide cometologists have come on board and verified what I believe is forensic evidence matching points on the head and body.
        Is it possible for you to point me to an image of the nested curve shapes mirrored on the neck? These should be interesting and would be too much of a coincidence to be seperately formed in roughly matching mirror patterns.

        • A.Cooper says:


          I've found the main two photos I used for the 'nested area' which I've linked, along with some more descriptions. Also, I note that you said:

          "Still no bona fide cometologists have come on board and verified what I believe is forensic evidence matching points on the head and body."

          Can you describe your matches as well or link a comment where they are described? I'd be interested 
          if they're the same as or similar to mine. 

          Anyway, these are the two main images I used for the portion of the shear line that includes the nested feature along with other correlations. Be sure to download the hi res versions and then you can toggle between them and zoom in. Again, I've described it as if fact to avoid politely qualifying every statement. It's still conjecture but I think it's got a lot more going for it than the theory that they are contact binaries (that happen to match along their perimeters) or a comet whose erosion has just recently reached a point where the two eroded edges happen to match each other very nicely. 

          I'll call the pic with the detail on the base, 'the base image' and the other one 'the head image'. It's best to have the base image rotated so the head is at top of frame.

          On the base image you can hopefully trace the shear line as described in my first comment above. Going from the left, it runs towards the very deep curved shadow nearly a quarter of the way along. That shadow is cast by the peak that fits into the deep recess in the head directly above it. This curved shadow thins as it tracks along the shear line and becomes the top edge of a long rectangular shape. There's a triangular shape that is contiguous with the bottom edge of the rectangle. The bottom of the triangle is slightly truncated. The rectangle is significant, the triangle just for orientation. 

          The rectangle is the flat slab area noted in the other comment. The recessed horseshoe shape is visible along its top edge. In the image used in the last description, you could only see the part that is encroaching on the rectangular slab. Notice the rectangle also has a fluted end to the right, as if scalloped out. The bottom flaring has two little marks or shadows which smudge the rectangular perimeter slightly. If you now look on the head (still on base image) you see a ring of four craters above the rectangle point below on the base. The bottom crater looks sliced off. To the left of it is the squared off overhang that was remarked on in a Rosetta blog post. The short end and long side of this feature roughly matches the dimensions of the rectangle below it. The right hand end is curved up at the edges and would fit into the scalloped part of the rectangle below. The two shadows in the fluted part may be dark, curved veins. If so, they match the dark curved veins in the underside of the head at that point (see head image). 

          In fact the whole bottom and side perimeter of the rectangle on the base is defined by a vein or narrow ridge that appears to be matched along the perimeter of the head before turning inward and curving round as it does on the base. 

          The horseshoe-shaped intrusion into the rectangle corresponds to the recess down to the bottom step of the nested step region I referred to in my other comment. There are at least 3 steps (incorporating two risers) but there appear to be two congruent platforms disappearing into the dust of the neck at the bottom. So it could be four steps making a sort of grand, curved staircase. 

          The very bottom platform that's almost disappeared in the dust curves round to somewhere near the upper right edge of the rectangle- although there is remaining material right against the rectangle at this point (sitting on what would be the extension of the bottom step).  So you would be looking in the head image for a sweeping curve running from the corner of the rectangle sweeping out over the underside of the neck to the left (the corner of the rectangle is the left edge of the obvious cove/crater on head- or the smaller sliced crater mentioned above if you include that as part of the cove). You would expect to see other nested curves running parallel to this longer curve out from the rectangle and to the left of it. That is what one can see in the head image. Moreover, there is a recess in the underside of the neck corresponding to where the material remains on the body and a finger-like protrusion at the point where the horse shoe is at its deepest. This finger on the neck underside extends to a point where it would touch or infringe the rectangle footprint as does the horseshoe. Both features don't look high enough or deep enough but they are the right shape and in the right place. And everything on the underside of the head in the head image is very flattened and foreshortened. Other images show more relief. 

          These corellations are not exact but they are very close and manifold. I would not expect an absolute clear-cut match because boulders and slabs between the joins would be ripped away in a somewhat ragged process. Evidence of this is apparent in the fact there are boulders nearby on the neck and that I believe a giant slab was pulled up from below the shear line (which used to be towards bottom of frame from shear line, incorporating the smoother detail that looks like cleaved rock, curving round left to where it hinged off with a messier break leaving more detritus). That giant slab is now missing, drifting away in the Roche pass or spin-up. 

          Moving along the shear line to the right of the rectangle in the base image, it dips inward (towards top of frame) for a very brief moment. This corresponds to that sliced-through crater next to the rectangle part on the head. Then it turns to run along the flat base of another sliced crater, this time on the base. This corresponds to the width of the crater/cove area on the head above. At the right hand side of this flat area on the base, there is a ridge that rises up to the highest crest of the rim round landing site A. This small rising ridge corresponds to the righthandmost edge of the cove above (see head image but beware of much foreshortening) In other pictures, both the edge of the cove and the ridge below it appear to match in their positioning and angle, though the head image here completely flattens this slightly upturned section. 

          I'll link a few more images that I used with a different perspective. I'll probably do that tomorrow. 

          • A.Cooper says:


            Here are some more photos I used. For the last photo I've recapped on a couple of things and described another striking match between head and body. 

            Top-down view of head:


            View from side from a little more clockwise viewpoint than other side views:


            View from above and lit from opposite side. Much detail that was in relief before disappears (whiteout) but other detail emerges:


            Best image for showing the shear line and missing slabs in relief:


            In this last link, you can see the biggest peak-the one that nestles into the recess in the head- as the most sunlit protrusion in the distance. Beyond that there is a flat strip leading to the end before you'd have to turn right to continue round the neck. The flat strip that looks almost like a roadway from all angles is the shadowed portion first described in my original comment above. The head rim used to sit on that flat strip.

             Moving to the foreground, you can see the truncated triangle with the rectangle appended except the rectangle now resembles two small triangles, joined end-to-end at their apexes, due to the shadow relief.  The triangle nearest us is the 'scalloped' section I mentioned before. It's where the end of the fluted rectangular portion of the head was seated. Yet more evidence of this is made apparent in this photo in the form of a distinctive ridge that climbs the body of the comet from way down, straight past the end of that scalloped triangle and continues in the head on the same line and angle. 

            This last image is also the best one for seeing the missing slab areas that resemble (missing) saddle bags slung in two places on the side of the body. They arc well below the shear line, half way down the side of the body. 

            By the way, in the first linked photo of my last comment you can see (hi res version) that most of the boulders on the neck in that region have tracks in the dust leading back to the nested step area. Even the group quite far to the right have tracks pointing in that direction but not all the way. This suggests to me that they are residue from the shearing process although it's surprising any tracks would remain from any process with the activity coming from the neck. 

            Just before posting this I found an exact match. I'll post that later.

          • Marco says:

            I've made some rough noted images in the following link.


            Numbers 1 to 10 are roughly the initial pointed descriptions of the shear line. The yellow dots mark out what I think you are saying is the rectangle. The yellow triangle is the one for orientation, the green curve is the scalloped section, and the blue circles are the 4 craters.

        • Marco says:

          Hi A Cooper. One thing I noticed when looking at the site A "missing slab" is that there appears to be a "slab" at the bottom of the cliff under the head on the 7th August pic,, roughly the right shape and size. It doesn't line up with the other head/body shear zones that you pointed out, but it might have lifted off and slid into that spot.

          • Marco says:

            Hi A Cooper. You ask which matches I have seen. The truth is, that I get a real sense that the comet has stretched, and the same features that you mention very specifically, I note in a more general sense, but I just cannot be sure because the right and proper way is with an accurate full 3D model with named features and a point matching system similar to fingerprinting to rule out random coincidences and spurious observations.
            I also have a sense that this is a normal progression for comets to split into two or more comets. That also goes for the "slabs" that have been sheared off - they become miniature comets (or shooting stars) of sorts, but mainly lobes that stretch until they break into two roughly spherical sub-comets.
            This is all a big deal, in scientific terms. Your detailed "feature-spotting" is definitely in that direction, and in lieu of a lack of feedback from scientists themselves, and a lack of even accurate scaled photos and virtually no named features, it is still very compelling and once confirmed, it should end speculation on ablation or contact binary as possibilities.

          • A.Cooper says:


            Your latest comment didn't have a reply button so I hope you'll see this, posted as a reply to your comment before that. 

             I've found a very close match between head and body in the area of the rectangle discussed in my last comment. 

            I reasoned that if I could find two side-view images, one of the rectangle and one of  the portion of the head that sits on it, they should show a side-on, or end-on, match in their vertical relief. By 'vertical', I mean their profile at right angles to the 'horizontal' geometrical layout discussed when looking down from above the head. 

            So I looked back through the photos for such end-on images. I was looking specifically for an end-on profile of the scalloped triangle at the end of the rectangle and an end-on profile of the rectangle shape on the head above that should show itself to be similarly fluted so that it nests inside the scallop.  So I was restricting myself to two specific points on the comet which under any normal circumstances would not have any chance at all of a match in this third dimension.  I simply suspected they might due to their very close match when viewed from above. 

            Then I saw the Rosetta blog post, "Cometwatch 9th December" posted on the 11th:


             It shows the rectangle not exactly end-on but in about 45 degree profile so enough to see the shape of the end profile. It's at the left hand edge, two-thirds of the way up. It looks less like a rectangle in this picture because the horseshoe takes a big chunk out of one side. The 'rectangle' incorporates the scalloped triangle that makes up one end, the end nearer the viewer, and the end-on profile of this triangle is, in turn, the edge nearest to the viewer. It casts a shadow so the end-on profile is the top of the shadow.  It shows a discinctive dip with two humps either side and if you trace the exact edge, it would resemble the profile of a child's schematic drawing of a seagull, with the right hand wing arcing over more prominently than the left.

             Then I noticed the portion of the head that supposedly sits on the rectangle. This is exactly edge-on so it's showing its end-on profile. It's the barely lit, spidery strip hanging down from the top left tip of the head. It's in a triangular shadow which is cast by what is in fact a strange looking overhang that's been remarked on before. The spidery strip is the actual section that would have sat on the rectangle, on top of the scalloped triangle. You can see it is v-shaped and extends upwards in a wing shape. It also extends downwards in a wing shape too. You can't see the downwards section in this photo but I found another one with the whole seagull wing profile, similarly end-on, from "Cometwatch - focus on the neck" on 8th October 2014. The blog post is linked below and the hi res photo link below that:



            It would be as well to include here also a link to a photo of the underside of the head so you can see the fluted v-shape from below:


            This underside photo clearly shows a fluted section even when at 90 degrees to end-on. It's the section at the end of the squiggly line and casts a shadow over the deep coved section. Incidentally, other matches while we're on this photo:

             1) the squiggly line matches features on the farthest long edge of the rectangle

             2) that squiggly portion of the head rim is kinked upwards too in a frill (other photos show this) so it nestles perfectly along the low, curved back ridge of the rectangle

            3) there is the finger of protruding rock that fits into to the horseshoe below and in another photo it shows two strata for the two layers in the horseshoe

            4) and there are the aforementioned nested features. 

            So there is a wealth of matching points just in this one small stretch. 

            As for the 8/10/14 photo showing the better end-on view of the fluted section, the features in this photo are easier to decipher if it's rotated 180 degrees because it's more in keeping with our view of the neck being a valley, in this case with the head to the right and the body to the left. 

            Assuming it is rotated, you see the head to the right, a small gap and then a very small portion of the body on the left. The head portion shows the cove or crater referred to in my last comment and the underside of the head, the 'cliff' in shadow. The body shows the scallop but not its end-on profile which is blocked by a ridge in the foreground. 

            At the far end of the cove, just under the cliff edge and in shadow, you can see the same distinctive 'v' shape which is turned 90 degrees on its side. Only its front edge is catching the sun. That front edge
            would have sat in the scalloped triangle below. If you zoom in, you can see that the v shape is only part of that front edge and it extends in a curve at both ends- at one end it goes to the very edge of the cliff and the other, down through a short stretch of shadow and probably kinking back up a tiny bit at the tip. So the entire end-on profile of this head section resembles the same child's schematic drawing of a seagull. It even has its lower wing arcing over more sharply than its upper wing which corresponds to the tighter right hand arc vs left in the scallop.

            I think that this matching of the fluted head section to the scalloped triangle and the wealth of other matches cited above are very strong evidence that the head broke away from the body and that the comet is not a contact binary or highly eroded single body. 

            P.S. One might object to the fact that the fluted head section would have to tip over about 45 degrees before being seated down onto the rectangle. I think it's nearer to 30 degrees, the rest being the usual photographic illusions. It looks like 30 degrees or less from the side views of the comet. This would be quite acceptable with the separate centres of gravity of head and body readjusting their relative orientation on a spin-up.  And as for a Roche pass with Jupiter, this tipping back of the head after rotating through bottom dead centre is a prerequisite. Also, I wondered about the slab at the bottom of the cliff. However, there seem to be striations that run through cliff and slab suggesting it was always attached. If it was always attached, it would fit very nicely in the dusty area between cliff base and Site A. In fact, in some top down photos there's a shape in the dust that vaguely resembles the slab- and that's where it would've come from in a stretch. 

          • A.Cooper says:


            I've published two articles on my blog, 'scute1133'. I think the annotated photo matches in these posts pretty well settle it. Feel free to visit, comment and spread the word!


            There are two articles so far and I may do another one later today. There may be a duplicate knocking about but it'll soon be apparent. It's identical save for a couple of typos and should get wiped.

          • Marco says:

            A.Cooper, that is so visionary, but solid logic. Enough to convince *scientists*. I admit that as soon as I tried to look in three dimensions, I got disoriented, so I could not achieve that watertight point by point detail matching in a reasonable amount of time. Keep going by all means to match the whole shear line. It will be fact on all good science journals - but it will have been on your blog first!

    • Andy says:

      @ A.Cooper

      Do you write descriptions of images for a living? If not, you should consider it as a future career. The visually impaired would surely welcome the wealth of detail that we sighted people take for granted but only you can describe in such meticulous detail.

    • Dave says:

      Hi A Cooper,

      I can understand what you are saying, and I can remenmber your original comments.

      Even so - some of the features have pieces cut right through them, ie some craters have flat bottomed vallies running right through them, there are other valleys that are very wide and run long distances, these definately dont look like subduction.

      I would not suggest there is no geological processes happening, but on top of possible subduction, possible impacts, there is a very coarse scouring thats taking place (for me this will be electrical) but I am not ruling out anything.
      I must admit though when I first looked at the neck, I could not decide whether it was a fracture or the join of a layer of rock/ice on top of the neck. Seeing the true nature of the errosion of the neck in the recent picture, then i guess it would not be such a surprise to see some cracks.
      The cracks were more believable when the theory suggested dirty snowball, but ESA says we have a very hard surface with good tenstile properties, not sure about toughness.
      Also, so much errosion is happening from the neck, I would of assumed that the comet was once much thicker at the neck, and has eroded away. Once the neck is thinner like now, I can see a crack possibly started, but on the evidence I would assume that the errosion came first. Then any fracture came second, so what ever is eroding the neck is the prime reason for the shape.

  • Cometstalker says:

    We had a few sounds from the comet and i would like to have some more. The link is a sound from saturn and a lot of EM-fields around bodies in our solar system are transfered into sound files. Some of those sounds are even musical. Even lightning on Earth make whistling sounds as the puls travels through the ionosphere.

  • Robin Sherman says:

    Hi Emily. As articles and papers from the Rosetta science teams are stating to appear in various Journals, would it be possible for a list of them to be maintained, perhaps on the Rosetta web page, so that we can try and access them?

    • Luc Faget says:

      Excellent proposal! I agree 200%!

    • Ian McWeen says:

      Good call. Seems to be very little info on this site. Is there another ESA page more up to date? I found this pic on another site: . First true colour pic of the comet as seen by OSIRIS. You should check this out . It's not grey at all!!! Please correct me if i'm wrong but is this info available anywhere on this site? I like this blog. Lots of intelligent banter. But we do need to be kept up to date. For example the picture I have linked to should be the banner headline! We have all heard Philae land thak you.

      Ian McWeen

      • Ian McWeen says: This realy needs to be here so we can discuss what the hell it's turned into. It is a different comet. We now seem to have brown and red/orange colouring. Organic molecules? Suddenly doesn't look like dust.

        • Robin Sherman says:

          Hi Ian. This colour image was mentioned by Bill Harris as the first comment on the 24/11/2014 blog post.

          The image you have posted is a tweaked version, I first saw on Reddit a couple of days later. The original image was made from successive OSIRIS images through different filters and as a result the three different colours don't quite match due to Rosetta's and the comet's motion between each capture. This meant it was not a very useful image. Some clever people out in internet land separated the images, adjusted for the motion and put them back together to give the image you have posted.

          The orange/red colour is indeed due to organic compounds, they have the generic name of Tholins.

          They key is they can not be present either without dust, or without volatile ices containing compounds such as Methane, Ammonia, Water and Carbon Dioxide. The colour is similar to the haze in Titan's atmosphere which contains, Methane, Ethane, Nitrogen and traces of Water vapour. The Moon and rocky asteroids are not this colour, because they do not contain these volatile ices in anything but trace amounts. The New Horizons mission to Pluto will take images that are likely to look a very similar colour, the Infra red spectra from Hubble and other telescopes have shown the characteristic absorption pattern of Tholins on the surface, as do a multitude of other Kuiper belt and outer solar system bodies.

          In effect this orange/red colour proves there is dust in large amounts all over 67P, since Tholins only form in the presence of silicate and other mineral dust. It also shows there must be other volatiles apart from Water and Carbon Dioxide, hence MIRO went looking specifically for Methanol and Ammonia, knowing there was a very high probability of finding them in large enough amounts to measure, which of course it has done. The interesting thing is that Sulphur containing volatiles have also been found. This means that the possibilities for biogenic compounds are greatly increased and if Phosphines are detected the whole gamut of basic starting compounds for proteins and metabolic processes, could be present.

          • THOMAS says:

            Hi Robin, you say "The orange/red colour is indeed due to organic compounds, they have the generic name of Tholins."

            You are perhaps a little too assertive. Nobody as yet knows anything whatever about the precise makeup of the comet nucleus's surface.

            My own theory is that the reddish colour is due to the predominance of ferric oxide Fe2O3, which gave Mars its nickname "The Red Planet".

        • Bruce says:

          Hi Ian,
          In these things the colours are all very approximate and depend very much on image processing.

          Remember 67P is basically very dark - as dark as charcoal. It absorbs 95% of the light that shines on it:

          I especially like this picture:

          With insufficient light your eyes would experience it as grey. If there is enough light it's not surprising it has a red-brown tinge given the preponderance of volatile organics that under the right circumstances can be synthesised into something like creosote - itself a deep red-brown colour. And it only takes a thin layer to change the colour of something.

      • Ian McWeen says:

        Thanks Bruce. At least your listening. That page was last updated two months ago. Must be more science by now. I read somewhere that ESA are releasing the colour photo I have linked to on the 15th Dec. Yet there it is in all it's glory on another website! This is very frustrating. I was hoping for the regulars here to coment on this picture.

      • Robin Sherman says:

        Thanks Bruce. One paper from the 90 plus quoted by Matt Taylor. I guess a few more might appear in tandem with the AGU conference next week. There is a list available anyway, which hopefully will be updated as and when.

        I have been trying to view earlier data from the Rosetta mission in the ESA Planetary Archive. Nothing is stored in any sort of standard format, PDF, JPEG, PNG etc. Helpfully it suggested you download various image processing programs, none of which my Mac would run. Why is a suitable program not available in the Apple App store for ESA or Nasa archives as they both run using the same formats? Just browsing the files brought my computer to a grinding halt. This is not public access, it appears purposely designed to prevent it. Is there a simple "how to" guide available? The instructions in the archive are totally inadequate for the general public.

    • emily says:

      Hi Robin, I see that this link has been shared already, but this is indeed a good starting point for our archive of published Rosetta papers, spanning the whole mission:

      • Robin Sherman says:

        Thanks Emily. I am persevering with the archive, I will try downloading the "Nasaview" software and see if that works.

  • Brian says:

    During a press conference back when the lander had finally come to rest, and they got those first photo's from the surface that they would have additional photo's from before when it first touched down and when it bounced back up and traveled a few thousand feet to the second touchdown. then bounced back up and traveled to the final touchdown. But I keep checking back and see nothing of this. I don't' understand why unless they thought they were going to get these pictures but didn't get them for some reason. But I remember the guy in charge said the camera on the lander would have these pictures from the first few touchdowns. anybody have any information at all on this?

    • Marco says:

      Simple Brian. Philae was spinning and airborne, so there was no way of knowing which direction the blurry, lined pictures were taken.

  • Dave says:

    Lots of people have mentioned the solar wind being collection of pos and neg charged ions. The point for the EU is the there is charge separation into shells hence Birkeland currents,
    The EU also accepts that a comet can achieve equalisation, but the comet is traveling very fast through the Suns charged environment. Also that it will pass through a varying charged field, hence there may be a continual potential where the energy of equalisation appears as a discharge to the surface. For some information about the nature of this charged environment please look at this video by Dr Michael Clarage, he proposes the nature of the charge separation and the voltage and currents available. It's on you tube - Dr Michael Clarage Understanding the electric sun 2014.
    He explains it preliminary data from the jet propulsion labs two satelites. He also admits it's not fully resolved and is happy to have discussion.

    Of course many have groaned ( Proff Harvey included) - EU no figures and no published papers
    So Here is a video but backed by published papers is a presentation from a Dr Pierre - Marie Robitaille, it nicely references his difficulties going against established science, being pilloried in the New York Times, seemingly disowned by his tutor and struggles with Kirchoffs law.
    The vid is on YouTube - Dr Pierre - Marie Robitaille Sun on trial.
    It's fully supported by papers I hope you enjoy it.

    • originalJohn says:

      Dave, those who groan about lack of quantitative data and publications to support the EU concept constitute a slightly desperate smoke screen. Much quantitative data which calls into question the gravity only theory of cosmology has been gathered in the era of excellent satellite and spacecraft technology. It is all published. Thousands of relevant documents are instantly available to those who look, using another piece of 20th century technology, the internet search engine. It is not of course flagged EU but that does not make it invisible. Much of the EU theory is centered on plasma physics but includes obviously other areas of knowledge too; astronomy, physics, chemistry, electronics and electrical engineering to name just a few.

      If quantitative data is not yet available that is not a problem. An alternative theory does not require a mathematical description at the outset. In fact a qualitative understanding helps to ensure that subsequent quantitative assumptions are valid. A mathematical analysis based on misconceptions is worthless. In the initial stages investigations are therefore of necessity qualitative, such as the excellent Stardust mission to comet Wild 2 to determine the mineral constituents of the nucleus.

      When even a fraction of the public funding consumed by mainstream institutions is accessible for EU investigations an enormous expansion in information and data will be possible.

      Until then it is left to the institutions, such as the ESA, to ask the appropriate questions. They have provided the instrumentation on the Rosetta mission to explore a comet nucleus and coma in unprecedented detail, including plasma and electrical properties. No doubt they will come up with data capable of satisfying all requirements.

      • Harvey says:

        There are lots of strange things to explain about comet behaviour, on that we can all agree.
        The EU ‘theorists’ jump from that fact to an ‘its all electrical’ explanation, which unfortunately raises far more problems than it solves.
        Because they *never* get into serious numbers or calculations, it is extremely easy to produce a credible sounding set of explanations, which simply do not accord with known physics. Sure, you can *start* with words; but you quickly need to move to first qualitative, does it scale properly etc, theories & then to numbers.

        You also need to be honest & complete in your use of data.
        A good example is the ‘the observed water is just OH from protons sputtering O off & combining with it, its not subliming ice’ argument.
        Firstly there is direct observational data, from an airborne telescope (Kuiper), a terrestrial telescope (Hawaii, forget which one) & Rosetta (MIRO) that neutral water *is* present, in large quantities; two different techniques (infrared, vibrational transitions, MIRO is microwave, rotational transitions), three different teams. Completely ignored in EU ‘theory’.
        The observed OH densities & general properties of the coma are entirely consistent with the UV photo dissociation od H2O model.
        The arrival rate of protons is *FAR* (many orders of magnitude) too low, & they are very inefficient at sputtering material off.
        If some mysterious, never explained in detail or quantified mechanism was concentration a vast area of solar wind on the comet (why? – most reduce it) there is a further problem; you will also be sputtering Silicon & the other elements & they should show up spectroscopically in the coma too at comparable levels to the oxygen; but they don’t. You can’t just sputter O & previously implanted protons or the surface will Si etc enrich.

        So everything we see is consistent with the comet degassing the water; essentially nothing is consistent with it originating from solar wind sputtering; a mechanism *which does exist*, & may be the dominant mechanism (on asteroids, the moon for example) – but is many, many orders of magnitude weaker.
        The EU theorist jump from ‘there is a problem’ (there is) via ‘this mechanism exists’ (it does) to ‘so its solar wind sputtering’ (does not hold water  .)

        A further piece of data was naked eye visible last night; our moon has no coma; why not id its solar wind sputtering, its easily close enough to the sun for a comet to form a coma, 67P will never get that close to the sun. Proton implantation/sputtering indeed happens there; on a tiny scale.

        A similar problem exists with the repeated claims it is solid rock.
        ESA have navigated Rosetta round 67P for months with great precision. Based on the gravitational interaction they quote a density of ~0.6kg/L, broadly consistent with every other measurement (about 4 or 5 I think, all below one) of a comet density. Now this is seriously weird, the comet seems to be partly hollow, & obviously its easier to explain if some of it has a density < unity; namely ice, consistent with the degassing.
        Big problem for the EU claims its solid rock, density ~2.5 to 3 or so – so it is claimed some mysterious electrical force is partially cancelling gravity & falsifying the mass. It seems to have happened every time, to a similar extent.
        But what is this force? – the only one available to act on Rosetta is the Lorentz force,
        The second term is a vector cross product; over an orbit it will point all over the place & behave nothing like gravity at all; its clearly ruled out, ESA could not navigate.
        The first term yields Coulomb’s law, Fe=k.(q1*q2)/r^2
        Now that *does* yield a force that scales like gravity, Fg=(G M1 M2)/r^2
        But there are two problems; if you try & put numbers in the charges (or rather charge product, all you can determine) is crazy & there is no mechanism to achieve it. Also a distance close to the body (& Rosetta has spent plenty of time at distances of only a few comet linear dimensions) it will only mimic gravity if the mass distribution & charge distribution are three dimensionally coincident.
        My credibility limit was passed a very, very long time ago; *everything* agrees with the sole forces on Rosetta being gravity & maybe a little drag close in.
        That means they have the density right, & its not solid rock.

        I have never, ever seen the EU community engage in the discussion at even this trivial level.

        Discharge issues in a separate post.

        • Dave says:

          Welcome back Harvey
          I been missing your numbers

          There must be data for the internal structure of the comet & hopefully for the composition and the structure of the surface.
          Maybe its best to wait for the Data for the moment, then maybe we find the missing ice, or maybe we find a hollow rock. Or maybe we have a surprise.
          I cant get exited either way until there is some data.

        • originalJohn says:

          Harvey, you can complain all you like about lack of mathematical theory. You can dismiss alternative possibilities with basic physics and figures and models chosen to support your preconceptions. It does not however disguise the fact that most aspects of cosmology are in a mess at this time. You do not presumably object to concepts of the solar system accretion disc, the Oort cloud and the icy nature of comets, because these are tenets of the standard model. There is though no observational evidence or mathematical theory to support them and in the case of accretion no plausible mechanism. They are just ideas. Accepted, consensus ideas. And even more so in the wider picture with black holes, neutron stars (try applying basic physics to them), dark matter, dark energy and dark flow. These are all ideas with no basis in reality yet they form the foundation of our cosmology. They are of course embroidered with mathematics to lend them credibility within the consensus but this does not detract from the perception that they are abstract and fundamentally meaningless.

          This Rosetta mission is an opportunity to expose the failings of our cosmology beyond just comets and to reveal some truths even if that was not he original intention. But it needs expanded thinking and perhaps a new understanding with no alternative ignored. Unfortunately for you those who support the status quo and who got us into the prevailing mess are not the ones who are going to sort it out. An approach is needed saying where have we gone wrong, not we are clever and right. You are of course entitled to your critical opinion but the lead and the enlightenment will come from elsewhere and in the fullness of time, after a description in plain language, it will have all the necessary mathematical, theoretical support and no disagreement with classical physics. .

        • Marco says:

          Hi Harvey, based on the gravitational attraction, they quote a density of ~ *0.4* kg/L.

      • Harvey says:

        So let’s turn to these mysterious discharges.
        Nothing like them on a scale *remotely* approaching, by many, many orders of magnitude, has ever been observed directly; they are purely ‘theoretical’, just like many things EU ‘theorists’ deride.

        Their exact mechanism is *never* discussed; it just apparently ‘obvious’; but unfortunately, it isn’t.

        Firstly, comparisons are made with EDM (electrical discharge machining) pits ~20um across, few microns deep, formed *on a conducting metal material* of which more later, *under oil* (yes, EDM is normally done under oil, over distances of microns.) This is compared to features km across; linear dimensions ~10^7, 10^8 bigger, volume of material removed ~10^21 to 10^24 times bigger, formed in very low pressures, on *insulating* bodies. Firstly the conditions are UTTERLY different, & the scale is like expecting what happens when I pull a Christmas cracker to look similar to the effects of a larger nuclear bomb than has ever been made by a very large fraction; such comparisons are meaningless.
        (I bought for my department & use regularly an EDM machine BTW.)
        Comparisons are also made to a spec of fused Fe2O3 which is a bit like 67P in shape. No scale bar, but it looks mm, sub mm, formed at high pressure, on a scale where surface tension would matter - & IGNORING other grains in the same field of quite different shape; choose the data that fits is not good science. Comparing things where completely different mechanisms operate is not good science.
        Once again the comparison is completely invalid & meaningless.

        Let’s think a bit about the discharge mechanism.
        Since these are sharp edged features on fast moving objects, the discharges must be of short duration; EU does sometimes say that, but doesn’t dwell on it.
        This means we have to store the energy electrically & release it fast.
        Ignoring wet electrochemistry (batteries) there are two obvious ways to store energy purely electrically, in a capacitor, 0.5 C V^2, and an inductor, 0.5L I^2
        EU clearly favours the first with its frequent references to charging etc, & its even harder to see how the second could work.

        The first point to note is that in general qualitative terms, 0.5 C V^2 is a very low energy density way to store energy. Megajoule capacitor banks are HUGE, a kg of TNT, or a modest projectile accelerated by a kg or so of propellant, is several MJ.
        Now C~k’’* Area/Distance
        To get a big C, you need big area for the capacitor ‘plates’ * a small distance between them. So great, the ‘plates are big aren’t they ‘, km sized – but oh dear, the distance is even bigger, & that reduces C; also the dielectric constant is unity, vacuum, that doesn’t help.
        But the HUGE problem is *THERE ARE NO CONDUCTING PLATES*. Rocky bodies etc are pretty good insulators. You could charge it all up – but the charge cannot flow transversely rapidly to form a localised high energy density EDM-ing discharge.
        EDM is *always* on conducting bodies to enable that lateral current flow to the localised damage area of current flow; *NEVER* on insulators.

        Then we are going to need a VERY high V, unimaginably high, to get enough energy.
        The solar wind is not just protons; there are plenty of electrons around.
        If the body tries to say go significantly positive (due to proton implantation maybe) it will start dragging in more electrons, & vice versa.
        Sure it can charge up but to trivial voltages.
        The peak energy in the solar wind is ~5keV; barely more than local substation voltages.
        There is a tail into the MeV, but *tiny* numbers & even if it somehow charged to that, mysteriously not roughly self-equalising, it can’t store enough energy for these cataclysmic events by a huge number of orders of magnitude.

        If everything is charging up like this, why wasn’t Philae destroyed on contact? Why aren’t there huge problems with spacecraft land on other in vacuum bodies? Why aren’t there huge problems with rendezvousing spacecraft etc (yes, they do take precautions against modest charging; nothing I’m saying excludes that.) The only claimed example I can think of it the initial flash from the TEMPLE impactor – but actually double flashes are well known from nuclear explosions for example, there are numerous non-electrical explanations.

        There is an ENORMOUS scientific literature which models the ‘electromagnetic’ aspects of the solar system, including comet bow shocks etc etc. There is lots to explain still, but EU just ignores that huge body of work.

        The EU ‘theorists’ simply never, ever engage with the problems in their ‘theory’.
        It is not, in any real sense, a theory at all; it jumps from the fact there are weird things which are hard to explain (true, great) via a heap of largely correct equations (that’s something) to the *assumption*, completely unsupported by observational evidence or detailed modelling, that ‘electric forces’ magically solve all this, *THEY DON’T*.

        • originalJohn says:

          Harvey, you seem to have a problem envisaging the possible scale of electromagnetic effects based on your own experience of such effects, or even the collective experience of humanity, tiny though it is in the theorised life of the universe. There is no theoretical limit on the scale of electromagnetic effects and because the force is so relatively enormous compared to gravity the effects can easily be reproduced and measured on a laboratory scale, as in your tiny EDM device, not just modelled.

          As you say to store a large amount of energy in a capacitor requires a large capacitor, but as you also note comets are large on that scale so why bother to make that point. And to charge or discharge a capacitor does not require metal conductors. This is an ideal built into devices to operate as effectively as possible as capacitors. It does not mean that no capacitance effect can occur in non ideal circumstances, such as lightning discharges to the surface of the Earth. And if you don't think a plasma arc can erode an insulating surface try it for yourself on a refractory brick, with an arc welder.

          Then to illustrate your perceived voltage problem you choose the example of a comet becoming positive in an environment of an abundance of electrons. You could equally have chosen a comet becoming increasingly negatively charged in that abundance of electrons, in the meagre proton environment you have described previously, but then the voltage is not such a problem.

          Then you state the solar wind energy as approximately 5 keV maxiimum. Does this approximation include 10 or 15 keV because it can certainly reach that uniformly on average and in CME s 30 or 50 keV. Not huge but why pick such a low figure. In plasma current, also, double layers can locally increase particle energies by many orders of magnitude.
          You finish by referring to enough energy for these cataclysmic events. I would hardly describe the discharge of plasma jets form the surface of comets as cataclysmic. You also claim elsewhere that there is no silicon in the coma. How can you know this. In view of the visible dust in the jets and the coma it would be extremely surprising if it contained no silicon.

          Finally to support your belief that nothing is charging up you say why wasn't Philae destroyed on contact. Indeed that was a possibility but fortunately it approached the nucleus at approx 3.7 km/hr giving ample time for charge equalisation to occur. NASA are well aware of this effect on spacecraft landers, and are investigating it at present for future planned manned missions to asteroids. With the DeepImpact copper projectile fired at comet Temple1 the relative approach speed was 37000 km/hr so an extreme discharge occurred. Interestingly despite the speed and the mission being called deep impact it was subsequently found that the impactor made no perceptible mark on the surface of the nucleus.

          Much of the mainstream literature refers to magnetic effects in isolation, without any cause, plasma with "frozen in" magnetic fields and to magnetic field lines and magnetic reconnection. All of these are theoretical impossibilities and mistaken understandings and in the case of the field lines absurd. They are not ignored. They are often commented on but they are irrelevant.

          • originalJohn says:

            I was wrong about CME s. The highest proton intensities recorded near Earth after a CME have been of the order of 1 GeV.

          • Harvey says:

            So for fun.
            If I take 1GV - the 1km radius body manages an energy equivalent to about 10^12J, or 250 tons of TNT.
            Which would be a fair old bang.
            In an 'extreme event',
            the particle flux for >100MeV is reported as ~100/(cm^2 s sr) for about two hours.
            You can entertain yourself by working out how long the body would take to charge 🙂 But as a clue, its a *LOT* longer than two hours!
            And of course neglects the fact that as it charges it will efficiently self neutralise, and that as an insulating body it cant deliver all the charge to a compact arc.................

          • Harvey says:

            Sorry, typo in the calculation. Its smaller, around 6*10^10J or about 15 tons of TNT.
            Not even a GV on a 1km radius body gives a bang much bigger than the largest WW2 bombs!

          • Prof Harvey Rutt says:

            I have no problem at all envisaging their scale, because I can, and have, calculated them. They do not remotely explain the claimed massive discharge phenomena. The EU community NEVER presents calculations to show they can.

          • Prof Harvey Rutt says:

            'Ample time for charge equalisation to occur'
            This is hard vacuum; you can hold of hundreds of thousands of volts *with a few centimetres gap* - I use equipment that does it all the time.

            The solar wind peak density is a few keV. Very small particle densities exist up to hundreds of MeV when CMEs occur, typically for a few hours, at *minute* densities.
            Of course spacecraft charge and it can threaten the electronics, that routine. Energies that can blow big crates in things are an entirely different matter.

            Just show us some sums!

    • Harvey says:

      His papers on Kirchoff's law are quite simply *wrong*.
      He even commits the most egregious of errors, a dimensionally incorrect equation (2).

  • Ana says:

    I hope you will find Philae soon.

    • originalJohn says:

      Harvey, I don't see why you are so obsessed with bangs and arc discharges. We don't normally see comets doing that. What we do see is a glow discharge for which the current requirement is about six orders of magnitude lower than for an arc. Then there is also the dark discharge which we don't see because visible photons are not emitted. The current for that is another four orders less. And the discharge is into a plasma not a vacuum. The voltage requirement is somewhat higher than for an arc but even a short period comet has years to become charged, towards the outer region of the planetary disc. Thereafter, as it approaches the Sun at speeds accelerating to 135000 km/hr in this case, the voltage is continuously maintained. As the current increases the discharge intensifies from dark to glow and more glow but not usually to arc even if a CME is encountered. Comet nuclei have, however, been seen to explode when impacted by a CME.

      In its several months of passage around the Sun the nucleus normally continues to discharge but if it becomes equalised with that region the jets, the coma and the tail could disappear, and this too has been observed. Sublimation would always be expected to continue at the peak radiation intensity nearer the Sun.

      Even if visible discharge has stopped near the Sun, as the comet moves away it can start to discharge again, sometimes violently and this too has been observed in several cases, well beyond the orbit of Jupiter in some. Hard to explain with sublimation.

      All of that is inferred, like the sublimation theory, from observation. It awaits measurements from this comet to confirm or refute it. You cannot refute it by modelling the environment in the vicinity of a comet nucleus about which you, or anybody else, know very little, particularly the actual voltages and currents in the plasma.

      Clearly you believe that the charge/discharge theory will be refuted in favour of the existing sublimation theory and I, and others, think the opposite, and I am as confident as you are. If it does prove to be an electric comet it is unlikely anyone will say " that can't be right, Harvey calculated it was impossible".

      By the way, if you remember the blindingly white flash from the Chelyabinsk meteor last year, that was an arc discharge.

    • originalJohn says:


      It's a plasma Harvey.

      • Prof Harvey Rutt says:

        It's hard vacuum; the plasma density is extremely low, the Debye length huge. The currents available tiny. Do some sums.
        People here continually fail to recognise the this; yes it's a plasma; yes there are currents; and they are MINUTE.

  • Wayne says:

    Robin Sherman and Kasuha and others may be interested in Thornhill's explanation of different features caused by electrical currents, some of which are seen on the comet.

  • Dave says:

    Sorry Kasuha,
    I directed you to the wrong Dr Clarage video,

    I should of written

    Dr Clarage Earths electric enviroment EU 2014.

    This shows the environment around the earth and the interaction with the sun, so this is the presentation, that shows the charged particals in shells and explains voltage and current.
    The point is the earth has a electrical conection to the sun, there will be one to the other bodies in the solar wind including the comet.
    However both presentations are relevent

    • Harvey says:

      Frankly, if these talks are the best the EU community can muster, the conventional establishment can sleep easy. They are hysterically bad. Strip away the pseudo-mystical stuff about 'purpose' and 'whether we are the most important', remove the half-baked & missunderstood regurgitation of other people's results, die laughing at analogies between a long-outdated atomic model & the changes to the Van Allen belts, and everything being analogous to an electrical transformer, and you are left with - nothing. No formulae, only throw away numbers, joke level vastly over simplified diagrams, no testable predictions.
      It had me creased up, quite literally.
      If you want to see something about the results from the Van Allen probes at semi-popular level, take a look here.

      • Sovereign Slave says:

        Harvey, when I read this post, I suddenly felt like I was in middle of a Big Bang episode listening to Sheldon lecture all the other physicists, including Dr. Clarage, about how stupid they were. Perhaps a spinoff show is in order, When Rabid Physicists Attack, cause they do often come across as intellectually ethereal high brows (which they often are, to their credit actually) engaged in intellectual one-upmanship. I liked your previous posts better, where you logically presented information that at least theoretically sounded quite damning to EU theory (and to which I would love to hear a qualified EU scientist reply, whether that happens or not). It is obvious that even within standard model, there are a huge number of competing theories and new emerging theories, looking at data in different ways, imagining various possibilities, and playing with math and models to support their theory or perspective. But one thing all these theories (BB, EU, etc) and any other theories have in common is that none of them adequately account for all that’s been observed and measured in space, all of them have some pretty glaring holes to point at, and all of them have their devotees who think their “right.” Obviously no one theory will prove to be all inclusively right, and as far as I can tell there is still a whole lot more that’s not known about space than is known about space. But regarding EU theory, it is already acknowledged I think by pretty much everyone that there are electrical processes of some kind that are taking place in space, and ESA has specifically equipped Rosetta/Philae to measure electrical phenomena related to P67. The question is whether electrical processes can account for more than was previously believed about what is observed in space, and I think that is still an open (and very valid) question, and won’t be adequately resolved until many more unknowns become known.

        • Dave says:

          Sovereign slave & Harvey,

          Have you seen this diagramme of Jupiter from the Cassini mission,
          there are plenty of other diagrammes and pictures of this structure and plenty of description

          it is a bit old hat now, but if this isnt electric what is?
          allegdedly can produce sychncotron and X ray radiation.

          The question was once is jupiter a very large comet.

          There is some reference in ancient art all over the world that it was. Even Nasa started an article with just that question.

          But really, is this an odd ball or the norm?

          • Gerald says:

            It's well-known, that Jupiter has a very strong magnetic field, trapping electrically charged particles, like the van-Allen belt around Earth, just much stronger.
            Even lightnings on Jupiter are surmised.
            Sun has a very strong magnetic field, too.
            That's based on serious science.

            But replacing most of gravity, or sublimation by electrostatic attraction is nonsense.

            There is no magnetic field around 67P strong enough to trap charged particles in any relevant way, nor is there an electric field strong enough to replace sublimation or gravity.

            Four fundamental forces are largely undisputed: gravity, electromagnetism, weak and strong nuclear force.
            Electromagnetism unifies electricity and magnetism. There exists an electroweak theory, which tries to unify electromagnetism and weak nuclear force.
            By general relativity, gravity is interpreted as curved space-time.
            There are serious attempts to unify gravity with the other three forces. But none of them is mature enough to be generally accepted.

          • Gerald says:

            Jupiter shows high abundance of hydrogen and helium. That's possible due to its strong gravity and large size, hence its high escape velocity, and since it's sufficiently far away from the Sun not to heat up the atmosphere to many thousand degrees necessary to make the hydrogen and helium escape.

            67P has high abundance of water and carbon dioxide, besides silicates, organics, and some other chemical species- Molecular hydrogen and helium are low.

            Hence there are fundamental differences in gravity and chemical composition between Jupiter and comets.
            Jupiter is also hot in its interiour, the comets aren't.
            Under high pressure hydrogen becomes metallic in the interiour of Jupiter. There isn't a high abundance of elemental metals in comets, but in some asteroids.

        • Gerald says:

          Of what I've seen sofar from the electric universe talks, they avoid scientific standards. Some fragments may appear like science to untrained people, but it's heavily flawy, hence hard to discuss seriously.
          Nice entertainment, not much nore.

          • originalJohn says:

            Gerald: You believe in and repeat the concept of metallic hydrogen simply because you have been told it exists. Perhaps you should be less trusting and look at it a bit more critically. It has been theorised that at extreme pressure hydrogen could achieve a state where the electrons, as in the metallic bond, are no longer tied to particular nuclei and are therefore free to conduct. Despite much trying for many years this state has never been achieved. It seems odd that it should have been theorised and odder that it is so readily accepted. Not the same theorisers but the same club has in the neutron star case the electrons under extreme pressure being crushed into the nuclei. I know we should not worry because that is just a theory too but it does not seem to fit well with the perhaps lower but still extreme pressure at the core of Jupiter liberating electrons, wouldn't you say.

        • Harvey says:

          Normally indeed I stick to the physics.
          But my remark does not relate to anything high brow or remotely 'one upmanship'. It relates to the showing of some basic competence in the field. This talk simply fails to do that; it is wrong from beginning to end. That is simply not arguable; its a fact.

        • Prof Harvey Rutt says:

          Actually, I thought about this further.
          This has nothing *whatever* to do with establishment v non establishment, EU v dirty snowballs, whatever.
          I would be saying *precisely* the same thing about this talk whatever 'side it was on', whatever subject was under discussion.
          It is simply grossly inaccurate. It does not meet the most basic standards of coherent argument and accuracy.
          If the EU community - indeed ANY community, in ANY context, wants to be taken seriously, it needs to do a very great deal better than this.
          This simply isn't arguable; if you actually know something about the subjects, this is, quite literally, laughable.
          That's not some reactionary establishment reaction; that's what it is.

      • originalJohn says:

        Well frankly Harvey if you think what you have seen is the sum total of the EU paradigm and all it has to offer then you have been lulled into a false sense of security. Those who promote the EU concept have minute resources to apply so they concentrate on speaking to the general population, those who pay the bills and are much more important than the academics, who only need to impress each other and themselves. NASA know this too, so they use wind and hosepipe and collision analogies, and picturesque artists impressions. Banging the academic drum gets you nowhere in the real world.

        • Prof Harvey Rutt says:

          unfortunately what they present to the public contains multiple, obvious, drastic scientific errors. This isn't remotely arguable if you know any actual physics; they are just wrong. They are also highly selective in their use of data, either ignoring (eg water emission) or denying (eg density) anything that doesn't fit. This is exactly what they complain the 'conventional' community do, but the EU community is far, far worse.
          Of course if you don't know any science, the glossy videos look convincing.
          The most interesting thing about it is the psychology, it seems to be nearer to a religion than to science.

  • Harvey says:

    For once, I think uncontroversial.....
    A number of people have enquired about published results to date. I just ran a search of one of the main academic databases, & found only one mainstream scientific publication containing Rosetta results so far; I ignored 'popular' type reports:

    "The rotation state of 67P/Churyumov-Gerasimenko from approach observations with the OSIRIS cameras on Rosetta "
    By:Mottola, S (Mottola, S.) et all
    DOI: 10.1051/0004-6361/201424590
    Published: SEP 2014
    Partial abstract: “Results. Evidence is found that the rotation rate of 67P has significantly changed near the time of its 2009 perihelion passage, probably due to sublimation-induced torque. We find that the sidereal rotation periods P-1 = 12.76129 +/- 0.00005 h and P2 = 12.4043 +/- 0.0007 h for the apparitions before and after the 2009 perihelion, respectively, provide the best fit to the observations. No signs of multiple periodicity are found in the light curves down to the noise level, which implies that the comet is presently in a simple rotation state around its axis of largest moment of inertia..................................”

    Unfortunately ‘Rosetta’ searches get a bit confused by things like the following  'Rosetta' doesnt mean the same thing to everybody!

    Participation of end users in the design of assistive technology for people with mild to severe cognitive problems; the European Rosetta project

    The Refractory Overactive Bladder: Sacral NEuromodulation vs. BoTulinum Toxin Assessment: ROSETTA trial

    The Rosetta Marbles from Feslegen, A-ren Unit, SW Anatolia

    Rosetta Structural Modeling of Tarantula Toxin Binding to Voltage Sensors

    • Marco says:

      A Cooper has mentioned this result in an earlier comment. There appears to be strong evidence that C-P has "stretched"into its current shape, and a couple of plausible mechanisms (Roche pass and spin-up/spin-down) for the forces to cause it. This peer reviewed research demonstrates a considerable spin up over one perihelion.

      • Prof Harvey Rutt says:

        If you take a twelve hour rotation, and 2km radius, the acceleration is around 4*10^-5g. So the forces exerted are minute. It would have to spin up by orders of magnitude for this mechanism to be significant.
        I guess a near Roche limit pass is in principle possible, but seems very unlikely. The range over which it will distort, but not break, is likely to be very small.

        • Marco says:

          Have you had a look at the forensic, fingerprint-style point matching between the head and body?

          Tell me that the head and body *by chance* have matching mirrored shear lines with 20+ points of match?
          Then tell me that there is a *More Plausible* explanation than a spin up/spin down, or Roche pass!
          Prof Harvey - show me the numbers and probability please.

          • Harvey says:

            Given the extent of the surface re-modelling that is *thought* to occur (we will be watchning) the surface should have little/no memory of events even an orbit or two back; so I'm sceptical of the detailed match. Its very easy to 'see' matching details; it would need proper image analysis demonstrating the match analytically to convince me.

            The numbers for the stretch/spin I gave/ the force is *minute* & it would have to spin up *massively*. The units were m^2/sec, not g, sorry, so ~10 times smaller in 'g'.

            I dont see a way to do a probility of stretch-not-break for a close near Roche limit pass in a simple way. Intuitively the zone over which this can happen is going to be small. It also requires it to act elastically, whereas its contituents (be they rock or low temperature ice) are brittle. Also the spin would tend to average it out, depending on the axis orientation & spin rate compared to near-Roche-limit time.
            So I wouldn't call it 'impossible', but I think it very unlikely.

            The 'terrain' forming process are complex & our intuition & 'general knowledge, common sense etc' utterly useless on 67P.

            One solution is to find an erosion process that causes an initial groove to grow in an unstable manner into this deep neck.Such processes could exist, due to the varying angle of incidence of the sunlight as it rotates for example; strange shapes get formed under laser ablation in vacuum - but on an *utterly* different scale & I am *not* suggesting a direct analogy. But I think it quite possible such a mechanism might exist.

            Hopefully the next few months will tell us far more; since other comets have shown this shape, a systematic mechanism seems likely, & makes low probability chance events like a pass at just the right distance unlikely, as we've seen it more than once.

            I have an open mind on how it formed; but these mechanisms dont appear very probable.

          • Harvey says:

            Actually I think there is a second reason cetrifugal stretchibg is unlikely, aside from the force being extremely weak.
            If you model it as a 'dumbell', with a certain initial angular momentum, & then stretch it, the force/unit area on the 'bar' *decreases* as the bar lengthens. So its very stable; if it tries to lengthen the tendency to do so decreases.
            I guess if this wasnt true a potter could not spin wet clay vases on a wheel.

            Two masses m separated by 2r initial angular momentum L


            so F=L^2/4mr^3
            (dimensionally correct at least 🙂 )
            'bar' area will reduce as r^2 so force/area varies as r^-1

            This arises because the force depends on w *squared*, whilst the angular momentum dependa on it *linearly.*.

            Anyone want to check; mechanics isn't my strong suit.

          • Marco says:

            Hi Harvey, Forensic "matching" has a solid foundation in science. It can be done from anything from partial fingerprint matching, shoe to partial shoe print, can fragments to the exact can opener that opened it, geological formations on the West coast of Africa with ones on the East coast of South America. In all these, the *mechanism* is secondary and irrelevant to the certainty in the relationship between the two items we are confirming a match for.
            Forensic matching is not rocket science, and it is not the same as "seeing faces in the rock" It can even be automated by computer with a percentage probability of match based on the number of points which match compared to what would be expected for random effects. Do some research if you wish. Check out mr Coopers link and check for yourself . Compare this with best practice for what is surely available online. I challenge you to find one single point of his which is not a matching point (direction and distance from previous in mirror fashion from other lobe) This is the only science that realistically make headway.
            All the maths regarding forces are merely speculations based on a complete lack of knowledge about what forces are required, because we don't know what materials in what state are where, what energy transformations are happening. It is microgravity with a delicate balance of forces. Maths which starts with guess upon guess is worse than useless.
            Imagine we are trying to match what looks like a partial shoe print on one side of the river to a shoe on the other. We shouldn't just say that a lot of things look like shoe prints, and that anyway, we cannot imagine how the shoe got to the other side of the river, nor why the shoe print didn't get washed away. First we do the forensic science, *THEN* we speculate on possible ways to explain the relationship with a model that is most likely given the match.

    • emily says:

      Indeed, the Mottola paper was referenced in our earlier blog post:

      And as mentioned in a previous post, you can find other Rosetta papers and publications listed here:

  • Jacob nielsen says:

    No news is good news? The idiom could be taking on a new meaning here where "tHe fUll Science pHase" (HUSH) means: no news, neither good or bad. So actually the meaning is: some news? Who knows?

  • Prof Harvey Rutt says:

    If you would like an 'advanced layman's' idea of the 'electrical environment of the earth', try this

    Please compare to the EU presentation cited above; this of course is just the Wiki summary, not the real scientific papers it's based on, which are far more rigorous and detailed.

  • Dave says:


    I thought that the Dr Pierre -Marie Robitaille would of been the article that interested you as its supported by published papers and has math

    • Harvey says:

      So I took a look over coffee.

      The talk I saw contains not one single original equation, just restatements of standard formulae.

      He appears to think that because lab black body sources have the blackest internal wall we can manage, this disproves Kirchoff's law. Perhaps he should talk to someone who uses them - I do. The walls are black because to get a given degree of approximation to a perfect black body, the blacker the cavity walls are to start with, the bigger the aperture you can tolerate for a given sized cavity. So its smaller, lighter, cheaper, uses less power; *thats* why we use black walls.

      I would *love* to take him down to the lab & show him something Ive seen many times.
      Materials are evaporated in vacuum to deposit thin films. One fairly common evaporation source is a tungsten tube, crimped shut at the ends, with a small hole in the side through which the evaporating material exits; its heated to typically 1-2000C by passing a current through it; so it glows quite brightly. Now the emissivity of tungsten in the visible is well under unity - so the *hole* always looks much brighter than the outside of the tube, which is at the same temperature, a fraction of a mm away, heated by the wall current. Its *brighter* because you are looking through the hole into the interior of the cavity & seeing the (nearly) black body radiation it contains escape. You can see it, by eye, easily.

      He is utterly confused about the fact that emissivity varies with wavelength (the Balfour-Stewart version he accepts!) and frequently confiuses cavity & non-cavity situations. He seems to think the fact that real materials dont follow Stefan's law is a problem; it isnt, you have to use the spectrally weighted emssivity. His discussion of gases, alumina etc is totally confused over this.

      And so on.

    • Harvey says:

      Since its slap bang in my field, I tracked down what I think is his most recent paper, On the Equation which Governs Cavity Radiation. Pierre-Marie Robitaille Volume 10 (2014) PROGRESS IN PHYSICS Issue 2 (April)

      Equation (2) of that paper *is dimensionally incorrect*, which invalidates the rest of it. Dimensional correctness is perhaps the most basic test one can perform of a formula's validity.

      He does not appear to understand the very equation he is trying to surplant. He confuses 'emissive power' which has dimensions) and 'emissivity' which does not. He incoorrectly states that the top line of equation (1) is the emissivity - it isn't, its the emissive power, typically with dimensions of W·sr−1·m−2·Hz−1 of Bν and W·sr−1·m−3 for Bλ.

      • Sovereign Slave says:

        Funny, I read his paper too, and immediately realized he was confused about emissive power vs emissivity, and that he was not only dimensionally incorrect, but inter-dimensionally incorrect as well.

        But seriously, I've got a proposal for you, Harvey. Given that it's appearing more and more evident that P67 is indeed just a big rock (as today's (12/12) article points out, no surface ice is confirmed and there's little to no compositional variation on the comet's surface), my suggestion is that you get ahead of the rush and use you're obviously formidable scientific superpowers to develop a model of how the coma is being formed from solid rock. As an exercise, just assume the comet is a rock and work backwards from there - based on all you know, what would be forming the coma and how if that were the case. Sure, it may wind up being an exercise in futility, but then again, maybe not, and I for one would be keenly interested in seeing what you come up with.

        • Prof Harvey Rutt says:

          I'm glad you find gross, obvious errors in a scientific paper funny; I dont.
          I was taught to check my formula's dimensional correctness as a schoolboy.

          There is no way to work back from a solid rock body to the observed coma, no mechanism exists. Furthermore this body has a density of 0.5kg/L, and rock has a density of c2.4-3
          It's bizarre, fascinating, and there is much to understand; but multiple, entirely separate bits of evidence show it's not solid rock.
          Our moon is - and has no coma.

      • Dave says:

        I will check for you, I am not sure that was part of the presentation.

  • Kamal Lodaya says:

    My source was journalist tweets from DPS retweeted in

  • Stuart Atkinson says:

    Thank you, Harvey. THANK YOU. At last someone with some numbers and FACTS. Great job.

    • Harvey says:

      Well here are some more for you.

      A spherical body 1km in radius would have a capacitance of a little over 0.1uF; textbook problem.
      If you charge it to 1MV (how....) it has a stored energy of around 55kJ; thats the equivalent of about 12g of TNT.

      To get it to 1GJ - the energy of a rather weak lightning strike, or a couple of hundred kg of TNT, would require well over 100MV. Yup, 100,000,000V

      (This assumes that the object discharges to something with sufficient opposite charge to allow it to fully discharge. The body it discharges too having more charge than that won't increase it; all it can do is neutralise itself.)
      This of course ignores the 'insulating body' problem.

      Then there is another little problem.
      Take a look at Paschen's law. Hard vacuum is really, really good at holding off high voltages, because the mean free path is huge & you dont get collisional cascades. Indeed vacuum circuit breakers are very compact - & I regularly use apparatus which holds off 3-400kV across just a few centimetres of high vacuum. So just how does the discharge get started? To all these cataclysmic events - which dont have anywhere near the energy to be cataclysmic - result from near brushing contacts? The mean free paths in interplanetary space are simply enormous (& will require *lateral* dimensions of that order too.) Could we have an explanation please?

      Somebody please correct my figures if I slipped up, it can happen.

Comments are closed.